Way back when the iTunes (Music) Store started, the record companies were clamoring for DRM to protect against Napster and other P2P sharing, and Apple obligingly complied with FairPlay. Over time, as the iPod became the portable device of choice, the record companies basically found themselves beholden to Apple, painted into a corner by that self-same DRM. Now they're giving up DRM on services like Amazon MP3 precisely to get access to the iPod without Apple.
The question for the future of DRM is whether subscription models like Rhapsody will take off and whether a hitherto reluctant Apple might embrace the subscription model as a response to the rise of other DRM-free download stores. In any case the article is worth a read for anybody interested in the future of digital media.